JPH11279433A - Blue multilayer interference pigment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a blue interference pigment excellent in light stability, chemical stability and weather stability. SOLUTION: This blue multilayer interference pigment having a platelet- shaped carrier and a covering layer covering the carrier has the covering layer with a layered construction obtained by laminating (i) the first layer comprising a colorless transparent metal oxide having a high refractive index, (ii) the second layer comprising colorless transparent metal oxide having a low refractive index and (iii) the third layer comprising cobalt aluminate, a cobalt- containing glass or cobalt oxide, in order.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a blue multilayer interference pigment.

[0002]

BACKGROUND OF THE INVENTION Colored interference pigments contain a colorant additive or a colored metal oxide. For those containing colored metal oxides, layers that produce interference colors may be formed. However, the color provided by these means is
Inevitably limited, in particular blue or bluish colors of a satisfactory brightness have not been obtained hitherto. In addition, colorants can greatly reduce the chemical and thermal stability of interference pigments, thus limiting the choice of the desired color.

US Pat. No. 3,951,679 describes a mica-based color pigment which is coated with a metal oxide layer and can further have a Prussian blue color coating. The Prussian blue layer is formed by reacting an iron compound precipitated on a substrate with water-soluble hexacyanoferrate. However, this pigment has room for improvement in that Prussian blue decomposes at temperatures between 200 and 300 ° C.

[0004] US Patent No. 4,968,351 discloses a pearlescent pigment colored with an adsorbent pigment. In the pearlescent pigment, a color lake is used in the colorant layer to enhance the adsorption of the colorant. However, when this pigment is brought into contact with an organic solvent, the organic colorant sometimes separates from the interference pigment. In addition, the organic colorant has a room for improvement because the weather stability of the pigment is impaired.

US Pat. No. 5,169,442 discloses a blue-green pigment. This blue-green pigment is composed of a substrate containing mica coated with a metal oxide, and an upper layer formed of a mixed oxide of magnesium oxide, calcium oxide, cobalt oxide and titanium dioxide. However, the mass tone of this pigment is not pure blue.

[0006]

An object of the present invention is to provide a blue interference pigment having excellent light stability, chemical stability, and weather stability.

[0007]

The above object is achieved by the present invention described below.

[0008] The present invention provides a blue mass tongue having a platelet-shaped carrier and a coating layer covering the carrier.
e) a multilayer interference pigment, wherein the coating layer comprises: (i) a first layer made of a colorless and transparent metal oxide having a high refractive index; and (ii) a second layer made of a colorless and transparent metal oxide having a low refractive index. And (iii) a blue multilayer interference pigment comprising a third layer composed of cobalt aluminate, cobalt-containing glass or cobalt oxide laminated in this order.

The present invention is also a blue multilayer interference pigment having a platelet-shaped carrier and a coating layer covering the carrier, wherein the coating layer comprises: (i) cobalt aluminate;
A first layer composed of a cobalt-containing glass or a cobalt oxide; (ii) a second layer composed of a colorless and transparent metal oxide having a high refractive index; and (iii) a third layer composed of a colorless transparent metal oxide having a low refractive index. Are laminated in this order, and a blue multilayer interference pigment.

[0010] The present invention is also a method for producing the blue multilayer interference pigment, wherein the carrier in the form of platelets is suspended in water,
The suspension is heated at 50-100 ° C., and the water-soluble metal compound is added at a pH suitable for hydrolysis, whereby a high refractive index metal oxide hydrate is precipitated on the suspended particles, Alternatively, by adding a base, the pH required for precipitation of each metal oxide hydrate is kept constant, and then the pH is adjusted to 4 to 10 with a base, and a water-soluble metal compound is added. The low refractive index metal oxide hydrate thereby precipitates on the suspended particles, while at the same time the pH is kept constant by adding an acid or a base, followed by washing the resulting product, Dried at 180 ° C., and 500-11
Calcination at 00 ° C., then bring the pH to 3-10, suspend the product in water, add the corresponding water-soluble metal oxide and hydrolyze the product with cobalt and aluminum oxide hydrate While maintaining the pH constant by adding a base at the same time, followed by washing the product, drying at 60-180 ° C., and 500-1100
And a method for producing a blue multilayer interference pigment, wherein the method is calcined at ℃.

The present invention also relates to a method for producing the above-mentioned blue multilayer interference pigment, wherein a carrier in the form of platelets is suspended in water.
The suspension is heated at 50-100 ° C. to a pH of 3-10, the product is suspended in water, cobalt and aluminum oxide hydrate are added by adding and hydrolyzing the corresponding water-soluble metal oxide. To maintain the pH constant by adding a base at the same time, followed by adjusting the pH to 4 to 10 with a base, adding a water-soluble metal compound, thereby adding a low refractive index metal. Oxide hydrate is precipitated on the suspended particles while maintaining the pH constant by the addition of an acid or base, followed by the addition of the water-soluble metal compound at a pH suitable for hydrolysis, whereby Establishes and maintains constant pH required for precipitation of each metal oxide hydrate by depositing high refractive index metal oxide hydrate on suspended particles and simultaneously adding acid or base And then the product It washed, and dried at 60 to 180 ° C., and a method of manufacturing the blue multilayer interference pigments and firing at 500 to 1100 ° C., about.

The present invention also relates to a method for producing a blue multilayer interference pigment as described above, wherein the material to be coated is subjected to intermediate drying.
The present invention relates to a method for producing a blue multilayer interference pigment, wherein the coating layer is formed by performing a CVD method in a fluidized bed reactor.

The invention also relates to the use of the above-mentioned blue multilayer interference pigments for paints, printing inks, plastics, cosmetics or ceramic or glass toppings, or to the above-mentioned blue multilayer interference pigments for laser marking of plastics. Regarding the use of

[0014]

DETAILED DESCRIPTION OF THE INVENTION The pigment of the present invention can be used as a mixture with a general commercially available pigment. Typical commercially available pigments include inorganic and organic adsorptive pigments, metal effect pigments and LCP pigments.

Suitable carrier materials for the pigments of the invention are natural or synthetic platelet-shaped materials which do not have an inherent color. A preferred carrier material is phyllosilicate (phyl
losilicate), metal oxide platelets and glass and ceramic pieces. Particularly preferred are mica, kaolin, synthetic mica, and metal oxide and silicon dioxide platelets.

[0016] Silicon dioxide platelets are described in International Application WO93 / 0823.
According to 7, it is produced by coagulating and hydrolyzing a water glass solution on a continuous belt.

The dimensions of the carrier material are not critical and can be tailored to a particular purpose application. Usually, the platelet-shaped carrier has a thickness of 0.05 to 5 μm, especially 0.2 to 2.0 μm. The other two dimensions are usually 2-100 μm, especially 5-5
50 μm.

The thickness of the individual layers of the pigment has a significant effect on the optical properties of the pigment. For pigments having a strong interference color, the thicknesses of the individual layers must be adapted to one another. Furthermore, by appropriately selecting the thickness of the layer, it is possible to provide a pigment whose color changes greatly depending on the viewing angle. For example, a thick SiO ₂ layer (layer thickness> 10
0 nm), it is possible to provide a pigment having a strong angle dependence of the interference color.

The thickness of each layer of the blue multilayer interference pigment of the present invention is preferably in the following range. : High refractive index metal oxide: 70 to 110 nm Low refractive index metal oxide: 60 to 110 nm Color imparting layer: 50 to 90 nm For example, the following components can be used.

Carrier material 25-40% by weight SiO ₂ 0.1-3% by weight TiO ₂ (metal oxide with high refractive index) 20-40% by weight SiO ₂ (metal oxide with low refractive index) 10-20% by weight CoAl ₂ O ₄ 10 to 35% by weight Tin dioxide has an effect of inducing rutile modification when titanium dioxide is used for the first layer. Tin dioxide is deposited directly on the carrier material. This technique is described in more detail in U.S. Pat. No. 4,867,794.

The metal oxide layer is preferably applied by a wet-chemical method, and it is possible to use the wet-chemical coating technique developed for the preparation of pearlescent pigments.
This type of technology is, for example, the German patents 14, 67, 468, 19, 59, 9
88, 20, 09,566, 22, 14, 545, 22, 15, 191, 22, 44, 298, 2
3,13,331, 25,22,572, 31,37,808, 31,37,809, 31,51,3
43, 31, 51, 354, 31, 51, 355, 32, 11, 602, 32, 35, 017, or further patent documents and other applications.

In the present invention, the coating layer is formed as follows. That is, the base particles are suspended in water, and one or more hydrolyzable metal salts are added. During the addition, the pH value is adjusted to a value suitable for hydrolysis. The pH value is also chosen such that the metal oxide and / or metal oxide hydrate is deposited directly on the particles without secondary precipitation. The pH is usually kept constant by adding a predetermined amount of base.

The formation of the coating layer can also be carried out by gas-phase coating in a fluidized-bed reactor, for example EP 0 045 851 and EP 0 106 235 for the preparation of pearlescent pigments.
Can be applied.

As the colorless transparent metal oxide having a high refractive index in the present invention, titanium dioxide, zirconium dioxide or tin oxide is used. Of these, titanium dioxide is preferred. Further, the colorless transparent metal oxide having a low refractive index of the present invention,
It has a lower refractive index than the high refractive index colorless and transparent metal oxide, and for example, silicon dioxide or aluminum oxide is used. Of these, silicon dioxide is preferred.

As a method for forming the titanium dioxide layer, the technique described in US Pat. No. 3,553,001 is preferable. An aqueous titanium salt solution is slowly added to the suspension of the material to be coated, which is heated to about 50-100 ° C., in particular 70-80 ° C., while simultaneously metering in a base, for example an aqueous ammonia solution or an aqueous alkali metal hydroxide solution. The addition maintains a substantially constant pH of about 0.5 to 5, especially about 1.5 to 2.5. TiO ₂
As soon as the desired layer thickness of the precipitate has been achieved, the addition of the titanium salt solution and the base is stopped.

This method, also called titration, is remarkable in avoiding excess titanium salts. This method
This is achieved by subjecting only a predetermined amount to hydrolysis. The predetermined amount refers to an amount necessary for uniform coating with hydrated TiO ₂ and the surface effective area of the coated particles can be accepted per unit time. According to such a method, hydrated titanium dioxide particles that do not precipitate are not generated on the surface of the particles to be coated.

The formation of the silicon dioxide layer is preferably performed by the following method. That is, the sodium silicate solution is
It is metered into a suspension of the material to be coated, which is heated to 50 to 100 ° C., in particular 70 to 80 °. The pH is adjusted to 4 to 10, more preferably 6.5 to 8.5 by simultaneously adding 10% hydrochloric acid.
To keep it constant. Following the addition of the silicate solution,
Stir for 30 minutes.

Precipitation of aluminum oxide hydrate on platelet-shaped material is known from US Pat. No. 4,084,983. The material is suspended in water and the suspension is carefully heated to a relatively high temperature, e.g. Next, an aqueous solution of an aluminum salt, for example, aluminum chloride, aluminum nitrate, potassium aluminum sulfate or an acidic aqueous solution of aluminum sulfate, or an aluminate, for example, an alkaline aqueous solution of sodium or potassium aluminate is added to the suspension. Supply. The concentration of Al ions in the feed salt solution is 0.1-5 mol / liter.
At the same time, an alkali or acid is added to achieve a pH of 3-10, preferably 4-9. Preferred alkalis include those containing an alkali metal hydroxide and ammonium hydroxide, particularly an aqueous NaOH solution or
Those containing NH ₃ gas are preferred. When acid is added, HC
l, H ₂ SO ₄ or HNO ₃ is preferred.

The addition of alkali or acid is adjusted so that the pH of the suspension is kept as constant as possible during the precipitation.

Regarding the precipitation of cobalt oxide hydrate, EP
0 342 533 is described in more detail. This is 4 ~
Occurs at a pH of 9. Since the precipitation conditions of cobalt oxide hydrate and aluminum oxide hydrate are substantially the same,
Coprecipitation of both oxide hydrates is possible.

When cobalt oxide is used for the color imparting layer, cobalt oxide hydrate is similarly deposited by the above-described process.

The procedure when a cobalt-containing glass is used as the color-imparting layer is described below.

Cobalt oxide hydrate and silicon oxide hydrate are co-deposited as a first or third layer on the carrier material under the above-mentioned conditions as a mixed precipitate. In this case, a glass structure is formed during firing of the product.

The tungsten bronze of the general formula M _x WO ₃ is
It can be similarly used as a color imparting layer. The alkali metal tungstate deposited on the carrier is then reduced with hydrogen or another suitable reducing agent to the extent that the compound of formula M _0.3 WO ₃ is formed. These tungstates are deep blue-purple.

Furthermore, the pigments coated as described above can be subjected to a post-coating or post-treatment process.
Thereby, light stability, weather resistance stability, and chemical stability can be further improved. In addition, the pigment can be easily handled, particularly, mixed into different media. Such post-coating and post-treatment processes are, for example, DE
-C 22 15 191, DE-A 31 51 354, DE-A 32 35 017 or
DE-A 33 34 598.

[0036]

The following examples are only for illustrating the present invention and do not limit the scope of the present invention.

Example 1 100 g of mica (10-60 μm) are suspended in 2 liters of deionized water and the suspension is heated to 75 ° C. with stirring. To pH 1.8 with dilute hydrochloric acid, SnCl ₄ · 5H ₂ O3.2g and 10ml37% HCl
Is metered in at a rate of 2 ml / min. During the addition, the pH is kept constant with 32% NaOH. After stirring for 30 minutes, 450 ml of TiCl ₄ solution (400 g / l)
Is likewise metered in at a rate of 2 ml / min. 32% NaOH
The pH is kept constant by simultaneous addition of. The pH is then adjusted to 7.0 with NaOH and the mixture is stirred for 30 minutes.
Here, a water glass solution (135 g of water glass which is 27% with respect to SiO ₂ diluted with 135 g of water) is metered in at a rate of 2 ml / min and the pH is kept constant by adding 10% HCl. After completion of the addition, stirring is performed at 75 ° C. for 10 minutes. Thereafter, the suspension is filtered with suction, the solid product is washed with deionized water to remove salts and dried at 110 ° C. After subsequent calcination at 800 ° C. for 30 minutes, the product is sieved and resuspended in 2 liters of deionized water. The pH was adjusted to 7.5 with NaOH and Co (NO ₃ ) ₂ .6H ₂ O 13
The pH is kept constant during the addition of the solution containing 2g and AlCl ₃ · 6H ₂ O 218g of deionized water 1200ml at a rate of 2 ml / min. The suspension is subsequently stirred for 30 minutes, suction filtered, the solid product is washed with deionized water to remove salts and dried at 110.degree. Next, the dried product is calcined at 1000 ° C. for 30 minutes, cooled and sieved. As described above, 290 g of a blue interference pigment having a gold color tone is obtained.

According to X-ray structural analysis, the pigment of the present invention is
Rutile modified mica TiO_TwoAnd CoAl_TwoO _Four(Spine)
It becomes.

The photoactivity of the pigments is in the range of commonly available TiO ₂ pigments.

Water immersion test (1 layer system, using normal paint)
The short term weathering results at are very good.

The achromatic color scale values [DIN 54001; ISO Standard 105 section A02] are as follows. 16 hours / 66 ° C. = 5-4, 20 hours / 80 ° C. = 4-5 Example 2 100 g of SiO ₂ pieces (prepared according to WO 93/08237) are suspended in 2 liters of deionized water and suspended. Heat the liquid to 75 ° C. Sn
Containing 40ml of Cl ₄ · 5H ₂ O12g and 37% HCl in water 370ml
The pH 1.8 solution is metered in at a rate of 2 ml / min. During the addition, the pH is kept constant with 32% NaOH. After the completion of the addition of the SnCl ₄ solution, the mixture was stirred for 10 minutes, and then 620 ml of the TiCl ₄ solution was added.
The (TiCl ₄ 410g / water 1 liter), weighed at a rate of 2 ml / min. During the conversion operation, the pH is increased by adding 32% NaOH.
Is kept constant. After 30 minutes, the pH is adjusted to 7.0 with NaOH and the water glass solution (190 g water glass diluted with 190 g water)
Is metered in at a rate of 2 ml / min and the pH is kept constant by simultaneous addition of 10% HCl. After the addition is completed, 75
Stir at 15 ° C for 15 minutes. The pigment is filtered off, washed to remove salts, dried at 60-180 ° C. and finally calcined at 800 ° C. for 60 minutes. Subsequently, it is sieved and the product is resuspended in 1250 ml of deionized water. Adjust the pH to 7.5, 100 g of Co (NO ₃ ) ₂
And AlCl ₃ · 6H ₂ O 164g of a solution containing in water 900 ml 2 ml
Per minute and the pH is kept constant with NaOH. The mixture is subsequently stirred for 30 minutes, filtered and washed, the solid product is washed to remove salts, dried at 60-180 ° C and 1000 ° C
Baking.

As described above, a gold-colored blue interference pigment is obtained.

[0043]

As described above, since the blue multilayer interference pigment of the present invention has a specific layer structure, it is excellent in light stability, chemical stability, and weather stability.

──────────────────────────────────────────────────続 き Continuation of front page (51) Int.Cl. ⁶ Identification symbol FI C09D 11/02 C09D 11/02 // A61K 7/00 A61K 7/00 B (71) Applicant 591032596 Frankfighter Str. 250, D-64293 Darmstadt, Federal Republic of Germany (72) Inventor Hans-Dieter Brückner Germany 64271 Darmstadt Merck Kargaea

Claims (16)

[Claims] 1. A blue multilayer interference pigment having a platelet-shaped carrier and a coating layer covering the carrier, wherein the coating layer is made of (i) a colorless transparent metal oxide having a high refractive index. (Ii) a second layer of a colorless transparent metal oxide having a low refractive index, and (iii) cobalt aluminate;
A blue multilayer interference pigment, wherein a third layer made of cobalt-containing glass or cobalt oxide is laminated in this order. 2. A blue multilayer interference pigment having a platelet-shaped carrier and a coating layer covering the carrier, wherein the coating layer comprises (i) cobalt aluminate, cobalt-containing glass or cobalt oxide. A first layer (ii) a second layer made of a colorless transparent metal oxide having a high refractive index, and (iii) a third layer made of a colorless transparent metal oxide having a low refractive index are laminated in this order. A blue multilayer interference pigment characterized by the following. 3. The blue multilayer interference pigment according to claim 1, wherein the platelet-shaped carrier comprises natural or synthetic mica, phyllosilicate other than mica, glass, aluminum oxide platelets or silicon dioxide platelets. . 4. The colorless transparent metal oxide having a high refractive index,
The blue multilayer interference pigment according to claim 1, wherein the pigment is titanium oxide, zirconium oxide, or tin oxide. 5. The colorless transparent metal oxide having a low refractive index,
It is silicon dioxide or aluminum oxide.
4. The blue multilayer interference pigment according to any one of 4. 6. The method for producing a blue multilayer interference pigment according to claim 1, wherein the platelet-shaped carrier is suspended in water.
The suspension is heated at 50-100 ° C., and the water-soluble metal compound is added at a pH suitable for hydrolysis, whereby a high refractive index metal oxide hydrate is precipitated on the suspended particles, Alternatively, by adding a base, the pH required for precipitation of each metal oxide hydrate is kept constant, and then the pH is adjusted to 4 to 10 with a base, and a water-soluble metal compound is added. The low refractive index metal oxide hydrate thereby precipitates on the suspended particles, while at the same time the pH is kept constant by adding an acid or a base, followed by washing the resulting product, Dried at 180 ° C., and 500-11
Calcination at 00 ° C., then bring the pH to 3-10, suspend the product in water, add the corresponding water-soluble metal oxide and hydrolyze the product with cobalt and aluminum oxide hydrate While maintaining the pH constant by adding a base at the same time, followed by washing the product, drying at 60-180 ° C., and 500-1100
A method for producing a blue multi-layer interference pigment, characterized by firing at a temperature of ° C. 7. The method for producing a blue multilayer interference pigment according to claim 2, wherein the platelet-shaped carrier is suspended in water,
The suspension is heated at 50-100 ° C. to a pH of 3-10, the product is suspended in water, cobalt and aluminum oxide hydrate are added by adding and hydrolyzing the corresponding water-soluble metal oxide. To maintain the pH constant by adding a base at the same time, followed by adjusting the pH to 4 to 10 with a base, adding a water-soluble metal compound, thereby adding a low refractive index metal. Oxide hydrate is precipitated on the suspended particles while maintaining the pH constant by the addition of an acid or base, followed by the addition of the water-soluble metal compound at a pH suitable for hydrolysis, whereby Establishes and maintains constant pH required for precipitation of each metal oxide hydrate by depositing high refractive index metal oxide hydrate on suspended particles and simultaneously adding acid or base And then the product It washed, and dried at 60 to 180 ° C., and 500 to 1100 manufacturing method of a blue multi-layer interference pigments and firing at ° C.. 8. The blue multilayer interference pigment according to claim 6, wherein the platelet-shaped carrier comprises natural or synthetic mica, phyllosilicate other than mica, glass, aluminum oxide platelets or silicon dioxide platelets. Manufacturing method. 9. The high-refractive-index metal oxide is titanium oxide, zirconium oxide or tin oxide.
The method for producing a blue multilayer interference pigment according to any one of the above. 10. The method for producing a blue multilayer interference pigment according to claim 6, wherein the metal oxide having a low refractive index is silicon dioxide or aluminum oxide. 11. The method for producing a blue multilayer interference pigment according to any one of claims 1 to 5, wherein the material to be coated is intermediate-dried and then subjected to a CVD method in a fluidized-bed reactor, to thereby obtain a coating composition. A method for producing a blue multilayer interference pigment, comprising forming a coating layer. 12. Use of the blue multilayer interference pigment according to claim 1 or 2 for paints, printing inks, plastics, cosmetics or ceramic or glass toppings. 13. Use of the blue multilayer interference pigment according to claim 12, for use as a mixture with other pigments. 14. Use of the blue multilayer interference pigment according to claim 1 or 2 for laser marking of plastics. 15. A paint, printing ink, plastic, cosmetic, ceramic or glass colored with the blue multilayer interference pigment according to claim 1 or 2. 16. A laser-markable plastic comprising the blue multilayer interference pigment according to claim 1 or 2.